/***
 * 
 * 画图为例：
 * IAPI :draw
 * Abstract: constroctor(IAPI api){} draw2
 * 
 * A extends IAPI:draw 
 * B extends IAPI:draw 
 * 
 * C extends Abstract:draw2
 * constroctor( api:IAPI，radius:int){}
 * 
 * 
 */

